String

.data
    HelloWorldString:
        .asciz "Hello World of Assembly!"
    H3110:
        .asciz "H3110"
.bss

    .lcomm Destination, 100
    .lcomm DestinationUsingRep, 100
    .lcomm DestinationUsingStos, 100

.text

    .globl _start

    _start:
        nop
        # 1. Simple copying using movsb, movsw, movsl

        movl $HelloWorldString, %esi
        movl $Destination, %edi

        movsb
        movsw
        movsl

        # 2. Setting / Clearing the DF flag

        std # set the DF flag
        cld # clear the DF flag

        # 3. Using Rep

        movl $HelloWorldString, %esi
        movl $DestinationUsingRep, %edi
        movl $25, %ecx # set the string length in ECX
        cld # clear the DF
        rep movsb
        std

        # 4. Loading string from memory into EAX register

        cld
        leal HelloWorldString, %esi
        lodsb
        movb $0, %al

        dec %esi
        lodsw
        movw $0, %ax

        subl $2, %esi # Make ESI point back to the original string
        lodsl

        # 5. Storing strings from EAX to memory

        leal DestinationUsingStos, %edi
        stosb
        stosw
        stosl

        # 6. Comparing Strings

        cld
        leal HelloWorldString, %esi
        leal H3110, %edi
        cmpsb

        dec %esi
        dec %edi
        cmpsw

        subl $2, %esi
        subl $2, %edi
        cmpsl


        # The exit() routine

        movl $1, %eax
        movl $10, %ebx
        int $0x80